Fabrication of Silver Chevron Arrays as an Efficient and Stable SERS Substrate: Implications in Biological Sensing

Although glancing angle deposited silver substrates offer an excellent figures for surface enhanced Raman scattering (SERS) sensing, the chemical instability issues of silver substrates upon exposure to the aqueous solutions is still challenging and limits their application in SERS-based biosensors. In this context, we applied and compared two different strategies including sodium citrate as a self-assembled monolayer (SAM), and thermal deposition of gold at different thicknesses to stabilize the silver chevron arrays deposited by the glancing angle deposition method. Although optical characterization confirms good stabilization in both strategies, intact morphological features can only be detected after gold coating compared to sodium citrate coating which makes a homogenous monolayer on the surface. Furthermore, the SERS intensity of Rhodamine B increases after these coating processes, which might be due to the less oxidation and deformation of the nanostructures on the substrate or improved attachment of the analyte to the substrates. This research can extend our knowledge for the development of stable and reproducible SERS substrates in the field of biological sensing.